The tub/shower in one of our bathrooms upstairs is not functional. We have a single handled Moen unit and the house is about 19 years old. The sink and toilet work great in this bathroom, but when we turn on the tub/shower, water comes out in about the same volume and pressure as a drinking fountain. When we pull the shower lever, water does not get to the shower head at all. We hired a plumber and he tried replacing the cartridge/valve, which did not work. He said that about the only other idea that he could come up with would be to pull the sink out, cut a hole in our wall, and replace the tub body to “see” if that fixed it. We would like to avoid that unless it is highly likely that this is the problem, due to the cost. All other plumbing in the house (including the sink and toilet in this bathroom and another full bath upstairs) works fine. The tub/shower in this bathroom has not worked since we bought the house 7 months ago. The inspector said that it worked for him, but it has never worked for us. Any suggestions would be greatly appreciated!

 

Take off the face plate (usually 2 screws). There may be a stop valve (shutoff valve) on each side of the valve body. With a flat blade screwdriver, rotate them back and forth then turn fully counter-clockwise to open them. Is there any change in flow?
If that doesn't do it, there may be a pressure balancing valve (shuttlecock) that is behind a large cap with a slot in it. Turn both stops off (clockwise) and with a large flatblade screwdriver, unscrew the cap. Don't lose the gasket under the cap. Work the shuttlecock out and clean it and the chamber. Don't scratch it up. It should slide in and out freely. Reassemble and open the stops. Does that help?

 

Thank you for your quick reply! I looked for the parts that you described, and I didn't locate them. My unit is a Chateau by Moen, which I believe must be very basic (especially since it's 19 years old). I didn't see any valves in the wall; only the pipes and cartridge. I tried leaving the water on for about 20 minutes tonight to see if there might be something lodged in the pipe that would work it's way out. The water flow never changed but I started hearing a popping noise about once every 15 seconds that sounded and felt (by the vibration on the wall) like it was coming from within the wall behind the toilet. If you enter the bathroom (shaped like a small rectangle), the sink is directly ahead on the left (far left corner) and tub/shower to the right (far right corner; the access to the pipes are through the drywall beside the sink). The toilet is in the front right corner (across from the tub) and the closet is in the front left corner (to the left of the toilet). I'm not very familiar with plumbing, so I'm not sure why I would be hearing this noise behind the toilet, and not the tub? The noise continued until about 15 to 20 minutes after I turned off the water. Does this make any sense?

 

Are you sure that there are no small valves on each side of the main valve, that have a slotted head?
Can you post a picture?

This is a strange one. If you don't have those shutoff valves so that you could shut off water to the valve, I would next turn off water to the house and relieve the pressure. Then pull the cartridge (unscrew and remove handle, pull out the brass clip holding cartridge and then pull the cartridge straight out). Using a pair of FRS radios (walkietalkies) have somebody turn on the water to the house while you observe. There should be a good stream of water shooting out of that valve and across the tub. If there isn't then there is an obstruction in the pipe to the shower. It could be valves not open fully or soft copper tubing that has gotten kinked.

I have no idea what the popping sound could be.

 

I took a picture, but the IMG option is turned off, so I am unable to post it. I did what you said about turning off the main water supply and checking the flow with the cartridge removed. It flowed out of the cartridge pipe with great force (shooting across the bathtub) without the cartridge. I, then, bought a new cartridge at Lowe's (with the same model #s) and it didn't work. It sounds like the pipe from the cartridge pipe to the tub spout may be clogged, but then why would it not be getting to the shower head either?

 

You can post pictures by going to a website such as Photobucket and make your picture into a link ( it's free) and put the link in your post. Good luck.

 

The problem must be in the cartridge. The orifices in the valve body are larger than in the cartridge. I cannot imagine them being clogged, especially to the tub spout.
I think that it is time to call Moen: 1-800-289-6636
They have excellent product support.

 

I called Moen and they said that there must be an obstruction in the pipe to the tub spout. I called another plumber out and they tried, unsuccessfully, to pull the obstruction out with a vacuum (after trying a new cartridge). They have never seen this before. They said that the piping to the spout will have to be replaced. At least we feel better about letting them cut into the wall now that it is the only remaining option. I really appreciate your help and input.

 

The pipe to the spout comes off of the bottom of the valve body and the shower comes off of the top of the body. You were getting little of no water out of both of them. If the pipe to the spout were somehow clogged, why isn't there water flow to the shower head?
Please post back when everything gets re-plumbed and let us know what was found as the cause of the no/low flow.

 

Just wanted to let you know that a plumber came in and replaced the tub/shower valve. It is clogged with something (I can't see what though). The water enters the area where the cartridge is and flows through another area (where the clog is) that is then routed either up to the shower or down to the tub spout. The tub works great now! Thank you for your assistance.